Sainsmart 5" TFT LCD Slow Refresh/Image Drawing

Hello all,
I’m new to the Arduino project and this is my first post. I recently purchased an Arduino Mega 2560 R3, and then a Sainsmart 5" TFT LCD. I learned how to import libraries and was a letter to create a basic sketch as they’re called that essentially uses a for loop and counts up, clearing the screen each time a new number is drawn.

The library I am using can be found here: UTFT Library
The display and shield I am using: Shield and Display

I have tried connection through the USB as well as using a 12V wall connection (Which seems to make the board very hot) but nothing changes. I found two tutorials using SainSmart displays here and here and both seem to have a much faster refresh rate (even though I know they are different sized displays I feel this is a sign faster drawing is possible) so I’m here asking for help. Have any of you used this display? What can I try to fix this issue?

Thanks in advance for any help.
-matt

Edit: My Code

#include <UTFT.h>

extern uint8_t SevenSegNumFont[];

// Uncomment the next line for Arduino Mega
UTFT myGLCD(CTE50,38,39,40,41); //ITDB32S

void setup()
{
  myGLCD.InitLCD();
  myGLCD.clrScr();
}

void loop()
{
    myGLCD.setFont(SevenSegNumFont);
    myGLCD.setColor(255, 255, 255);
    for(int i = 0; i < 30; i++)
    {
    myGLCD.print(String(i), 300, 200, 180);
    myGLCD.clrScr();
    }

  while (true) {/*do nothing*/};
}